Various systems exists for controlling irrigation water flow. The most common are hand operated valves where an operator manually turns the water on when he wants to irrigate and off after sufficient irrigation. Valves are available which can be preset to close after a predetermined quantity of water has passed through. These valves are substantially more expensive than hand operated cutoff valves. Elaborate systems exist for detecting ground moisture and determining when irrigation should be started. Electrically controlled valves are available which will turn irrigation valves on and off on a predetermined schedule. Sometimes the irrigation is started in the middle of a rain storm, and these systems are expensive compared to the hand operated system.
What is needed is a completely automatic, cheep irrigation control valve system which will never turn the water on in the rain.